[Atypical transformation of cell populations after low irradiation and other actions]

Ionizing irradiation at low doses and some weak non-irradiational (including non-mutagenic) actions can produce a peculiar cell reaction, such as a massive, dose-independent transition to a new regime of existence. The changes appear saltationally. They are maintained for a very long time by both rarely and actively dividing cells. The most characteristic phenotype of the studied transformation is a stable increase of probability of cell damage and death. Some other manifestations of this transformation have been also revealed. This unusual response is found upon observation of totally different biological objects (unicellular organisms, cells of various mammalian tissues) to be regarded as a general biological regularity. The role of such radiational alterations in pathogenesis of remote consequences of low-dose irradiation is discussed.